package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.FLOWER_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //1.获取当前登录用户id
        Long userId = UserHolder.getUser().getId();
        String key = FLOWER_KEY + userId;

        //2.判断关注还是取关
        if (isFollow){
            //3.关注
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            boolean isSuccess = save(follow);
            if (isSuccess){
                //保存数据库成功，以set结构保存数据到redis中，实现共同关注
                stringRedisTemplate.opsForSet().add(key, followUserId.toString());
            }
        }else {
            //4.取关
            boolean isSuccess = remove(new QueryWrapper<Follow>().eq("follow_user_id", followUserId).eq("user_id", userId));
            stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
        }

        return Result.ok();
    }



    @Override
    public Result followOrNot(Long followUserId) {
        //1.获取当前登录用户id
        Long userId = UserHolder.getUser().getId();

        //2.查询当前用户是否关注该用户
        Integer count = query().eq("follow_user_id", followUserId).eq("user_id", userId).count();

        return Result.ok(count > 0);
    }

    /**
     * 查询共同关注
     * @param id
     * @return
     */
    @Override
    public Result followCommons(Long id) {
        //1.获取当前登录用户id
        Long userId = UserHolder.getUser().getId();
        String key = FLOWER_KEY + userId;

        //2.求交集
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key, FLOWER_KEY + id);
        if (intersect == null || intersect.isEmpty()){
            //没有共同关注
            return Result.ok(Collections.emptyList());
        }

        List<Long> ids = intersect.stream()
                .map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> userDTOS = userService.listByIds(ids).
                stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(userDTOS);
    }
}
